CN210679750U

CN210679750U - Slag-proof structure of welded combined cable reel

Info

Publication number: CN210679750U
Application number: CN201921245779.8U
Authority: CN
Inventors: 苟举才
Original assignee: Individual
Current assignee: Individual
Priority date: 2019-08-02
Filing date: 2019-08-02
Publication date: 2020-06-05
Anticipated expiration: 2029-08-02

Abstract

The utility model discloses a slag-proof structure of a welding combined cable tray, which comprises a first cable tray body, a barrel body and a second cable tray body; the glue blocking ring and the welding ring are of annular structures, the glue blocking ring and the welding ring are arranged at the central part of the side surface of the first line tray body and are coaxially arranged with the first line tray body, the inner diameter of the glue blocking ring is larger than the outer diameter of the barrel body, and the outer diameter of the welding ring is not larger than the inner diameter of the barrel body; a welding groove is formed between the glue blocking ring and the welding ring; the upper part of the welding ring is also provided with a leading-in inclined ring surface, and the outer side wall of the inclined ring surface extends outwards from top to bottom step by step so as to guide the cylinder body to be inserted into the welding groove during welding. The utility model discloses a keep off gluey ring, butt fusion groove and cut down the structural design of face for the outside of the butt fusion junction of line disk body and barrel forms the ring form and blocks the face, prevents effectively that the sizing material after the melting in-process melts from flowing or throwing away, makes the sizing material along keeping off gluey even packing of ring in the butt fusion inslot, has guaranteed the butt fusion quality effectively.

Description

Slag-proof structure of welded combined cable reel

Technical Field

The utility model relates to a plastics field indicates a prevent sediment structure that is used for butt fusion combination cable dish that drum was made very much.

Background

The wire coil is used for machine cabling, turnover and the like of wires and cables at the earliest, the application field of the wire coil is gradually expanded along with the development of various industries, but the wire coil is mainly used for packaging containers of corresponding products, and becomes an indispensable matched product for winding and storing wires, cables and the like. With the development of the plastic industry, the strength and hardness of plastics are generally improved, so that the plastic wire coil gradually becomes a mainstream wire coil structure due to light weight and high strength.

The existing plastic wire coil can be integrally injection molded, the process adopts an integral injection molding process, and the whole wire coil is injection molded in place at one time by an injection molding machine through designing a set of complete wire coil molds; in addition, in recent years, there has been developed a cable drum manufactured by "fusion bonding" in which a single drum or barrel is injection-molded in advance, a plastic portion of a portion of the drum in contact with the barrel during rotation is melted by heat generated by rotational friction through a relatively high-speed rotational movement after the drum is brought into contact with the barrel to form a molten-state or semi-liquid-state plastic fluid, and the fluid flows into a joint gap between the barrel and the drum and solidifies when the temperature is lowered, thereby fixedly joining the drum and the barrel. Compared with the traditional cable reel processing technology such as integrated molding, the process for manufacturing the cable reel by the melting mode has many advantages, such as simplifying the manufacturing and production cost of the molding die, reducing the process difficulty, improving the production efficiency and the like; the manufacturing process of the welding cable reel is the development direction and trend of the future industry.

However, in the actual application process of the cable reel welding process, some technical defects need to be solved, in the actual production process, the melted rubber material is liquid or semi-liquid fluid, due to the high-speed rotation of the welding part, the molten rubber can flow out or be thrown out from the gap between the two joint surfaces in the joint process under the action of centrifugal force, the left molten rubber can form welding slag or craters, and the thrown molten rubber can cause material waste and hurt to people, so that the quality of products is affected. The subsequent treatment of the welding slag or the craters not only increases the cost, but also is difficult to achieve the ideal effect. In addition, the molten fluid can not flow uniformly at the welding position in the welding process, so that the connection strength of the molten connection part after cooling and condensation is different, and the welding quality can not be ensured.

SUMMERY OF THE UTILITY MODEL

The to-be-solved technical problem of the utility model is not enough to above-mentioned prior art, provide one kind through keeping off gluey ring, butt fusion groove and cut down the structural design of face for the outside formation ring form of the butt fusion junction of drum and barrel blocks the face, prevents effectively that the sizing material after the butt fusion in-process melts from flowing or throwing away, makes the sizing material along keeping off gluey even packing of ring in the butt fusion inslot, has guaranteed the butt fusion quality's butt fusion combination cable dish effectively and has prevented the sediment structure.

The utility model adopts the following technical scheme: a slag-proof structure of a welded combined cable tray comprises a first cable tray body, a barrel body and a second cable tray body, wherein the first cable tray body, the barrel body and the second cable tray body are made of plastic materials; the glue blocking ring and the welding ring are of annular structures, the glue blocking ring and the welding ring are arranged at the central part of the side surface of the first reel body and are coaxially arranged with the first reel body, the inner diameter of the glue blocking ring is larger than the outer diameter of the barrel body, and the outer diameter of the welding ring is not larger than the inner diameter of the barrel body; a welding groove is formed between the glue blocking ring and the welding ring so that the cylinder body can be inserted for welding; when the cylinder made of plastic and the first line disk body are welded in the welding groove in a relative high-speed rotating motion mode, the rubber blocking ring blocks liquid or semi-liquid fluid formed after the cylinder and the first line disk body are melted due to high temperature in the welding process, the liquid or semi-liquid fluid is prevented from overflowing, and after the temperature is reduced, the molten fluid, the rubber blocking ring, the welding ring, the first line disk body and the cylinder body are connected and fixed into a whole.

Preferably, the second reel body and the barrel are integrally injection-molded to form an integral structure; the first reel body and the barrel are connected in a melting mode to form an integral cable reel, when the first reel body and the barrel are welded in a relatively high-speed rotating mode, liquid or semi-liquid fluid formed by heating and melting flows along the annular welding groove and is uniformly filled in the welding groove; after the welding is finished, when the temperature is reduced, the plastic fluid is condensed and fixed at the welding joint of the first line disk body and the cylinder body to form an annular uniform connecting part.

Preferably, the glue melting surface on the outer side wall of the cylinder body is provided with an annular cut-down surface, and the cut-down surface is inwards recessed along the outer wall of the cylinder body to form an annular recessed step surface so as to increase the glue containing volume in the glue blocking ring; when the first line disk body is welded with the cylinder body, plastic fluid is filled into a gap between the cut surface and the glue blocking ring, and the first line disk body is fixedly connected with the cylinder body after the fluid is condensed and fixed.

Preferably, the upper part of the welding ring is further provided with a lead-in inclined ring surface, and the outer side wall of the inclined ring surface extends outwards gradually from top to bottom so as to guide the cylinder body to be inserted into the welding groove during welding.

Preferably, the inner wall of the cylinder body is provided with a guide inclined ring surface, and the inner side wall of the inclined ring surface extends outwards gradually from bottom to top so as to guide the cylinder body to be inserted into the welding groove during welding.

The slag-proof structure of the fusion-spliced cable reel comprises two wire reels and two bobbins, wherein the bobbins are of cylindrical structures, and the two wire reels are respectively detachably connected to two ends of each bobbin and are fixedly connected with the end parts of the bobbins through fusion; the welding device also comprises a glue blocking ring, a welding ring and a welding groove, wherein the glue blocking ring and the welding ring are of annular structures, the glue blocking ring and the welding ring are arranged at the central part of the side surface of the wire coil and are coaxially arranged with the wire coil, the inner diameter of the glue blocking ring is larger than the outer diameter of the barrel, and the outer diameter of the welding ring is not larger than the inner diameter of the barrel; a welding groove is formed between the glue blocking ring and the welding ring so that the cylinder body can be inserted for welding; when two ends of the plastic cylinder body respectively rotate at a high speed relative to the two wire coils in the welding groove for welding, the glue blocking ring blocks liquid or semi-liquid fluid formed after the cylinder body is melted due to high temperature when the cylinder body is welded with the two wire coils, the liquid or semi-liquid fluid is prevented from overflowing, and after the temperature is reduced, the melted fluid, the glue blocking ring, the welding ring, the wire coils and the cylinder body are connected and fixed into a whole.

Preferably, the outer side walls of the two ends of the bobbin (8) are provided with melt glue surfaces or annular cut surfaces (6), the cut surfaces (6) are inwards recessed along the outer wall of the bobbin (8) to form annular recessed step surfaces, so that the glue containing volume in the glue blocking ring (4) is increased; when the first reel body (1) is welded with the bobbin (8), plastic fluid is filled into a gap between the cut-off surface (6) and the glue blocking ring (4), and the reel (7) and the bobbin (8) are connected and fixed after the fluid is condensed and fixed.

Preferably, the upper part of the welding ring is further provided with a leading-in inclined ring surface, and the outer side wall of the inclined ring surface extends outwards gradually from top to bottom so as to lead the bobbin to be inserted into the welding groove during welding.

Preferably, the inner wall of the bobbin is provided with a guiding inclined ring surface, and the inner side wall of the inclined ring surface extends inwards from the end part of the bobbin to the middle part gradually, so that the guiding barrel is inserted into the welding groove during welding.

The beneficial effects of the utility model reside in that:

the utility model discloses defect and not enough carry out the improved generation innovation to prior art exists, designed one kind through keeping off gluey ring, the weld ring, the structural design of butt fusion groove and reduction face, keep off gluey ring and butt fusion groove and set up in the side central part position of drum, and keep off and form annular butt fusion groove between gluey ring and the butt fusion groove, the barrel inserts the weld inslot, and the high-speed rotary motion of relative drum carries out the butt fusion action, make the drum block the face with the outside formation ring form of the butt fusion junction of barrel, prevent effectively that the sizing material after the butt fusion in-process melts from flowing or throwing away, and make the sizing material along keeping off gluey even packing of ring at the butt fusion inslot, the slag-proof structure of butt fusion combination cable dish of butt fusion quality has been guaranteed effectively. Specifically, the utility model is provided with an annular glue blocking ring at the fusion joint of the disc surface of the upper and lower wire coils and the cylinder body; an annular welding groove is formed between the ring surface of the glue blocking ring and the welding ring, and the width of the annular groove is slightly larger than that of the cable reel cylinder body; during welding, the cylinder is inserted into the welding groove, and molten glue overflowed due to centrifugal action is blocked in the welding groove by the glue blocking ring, so that on one hand, the welding bonding strength is increased, the fluid plastic material in a molten state can be uniformly distributed along the welding groove in the welding process, the welding connection uniformity is ensured, and on the other hand, surface scars or welding slag are avoided; the utility model discloses can cut down the round at barrel joint end surface, this cut down the face and keep off the space of gluing between the anchor ring face and be used for holding and spill over the melten gel.

Drawings

Fig. 1 is one of the schematic structural diagrams of the component detachment according to embodiment 1 of the present invention.

Fig. 2 is a second schematic view of the component detachment structure according to embodiment 1 of the present invention.

Fig. 3 is one of the component separation structural diagrams of embodiment 2 of the present invention.

Fig. 4 is a second schematic view of the component detachment structure according to embodiment 2 of the present invention.

Fig. 5 is a schematic perspective view of embodiment 2 of the present invention.

Detailed Description

The invention will be further described with reference to the accompanying drawings:

example 1: as shown in fig. 1 to 3, a slag-proof structure of a welded combined cable tray comprises a first tray body 1, a cylinder body 2 and a second tray body 3, wherein the first tray body 1, the cylinder body 2 and the second tray body 3 are made of plastic materials, the cylinder body 2 is of a cylindrical structure, and the first tray body 1 and the second tray body 3 are arranged at two ends of the cylinder body 2 in parallel at intervals; the welding line tray further comprises a glue blocking ring 4, a welding ring 5 and a welding groove A, wherein the glue blocking ring 4 and the welding ring 5 are of annular structures, the glue blocking ring 4 and the welding ring 5 are arranged at the center of the side face of the first line tray body 1 and are coaxially arranged with the first line tray body 1, the inner diameter of the glue blocking ring 4 is larger than the outer diameter of the barrel body 2, and the outer diameter of the welding ring 5 is not larger than the inner diameter of the barrel body; a welding groove A is formed between the glue blocking ring 4 and the welding ring 5 so that the cylinder body 2 can be inserted for welding; when the cylinder 2 made of plastic and the first line disk body 1 perform relative high-speed rotary motion in the welding groove A for welding, the glue blocking ring 4 blocks liquid or semi-liquid fluid formed after the cylinder 2 and the first line disk body 1 are melted due to high temperature during welding, the liquid or semi-liquid fluid is prevented from overflowing, and after the temperature is reduced, the melted fluid and the glue blocking ring 4, the welding ring 5, the first line disk body 1 and the cylinder 2 are connected and fixed into a whole.

Preferably, the second wire coil body 3 and the cylinder body 2 are integrally injection-molded to form an integral structure; the first reel body 1 and the barrel body 2 are connected in a melting mode to form an integral cable reel, when the first reel body 1 and the barrel body 2 rotate relatively at a high speed to perform welding, liquid or semi-liquid fluid formed by heating and melting flows along the annular welding groove A and is uniformly filled in the welding groove A; after the welding is finished, when the temperature is reduced, the plastic fluid is condensed and fixed at the welding joint of the first line disk body 1 and the cylinder body 2 to form an annular uniform connecting part.

An annular cut-off surface 6 is arranged at the position of the glue melting surface on the outer side wall of the cylinder body 2 or is arranged on the outer side wall of the cylinder body 2, the cut-off surface 6 is inwards sunken along the outer wall of the cylinder body 2 to form an annular sunken step surface, so that the glue containing volume in the glue blocking ring 4 is increased; when the first line disk body 1 is welded with the cylinder body 2, plastic fluid is filled into a gap between the cut surface 6 and the glue blocking ring 4, and the first line disk body 1 is fixedly connected with the cylinder body 2 after the fluid is condensed and fixed.

The upper part of the welding ring 5 is also provided with a leading-in inclined ring surface B, and the outer side wall of the inclined ring surface B extends outwards gradually from top to bottom so as to guide the cylinder body 2 to be inserted into the welding groove A during welding.

The inner wall of the cylinder body 2 is also provided with a guide inclined ring surface B, and the inner side wall of the inclined ring surface B extends outwards gradually from bottom to top so as to guide the cylinder body 2 to be inserted into the welding groove A during welding.

Further, the utility model discloses a through keeping off gluey ring, the weld ring, the structural design of butt fusion groove and reduction face, keep off gluey ring and butt fusion groove and set up in the side central part position of drum, and keep off and form annular butt fusion groove between gluey ring and the butt fusion groove, the barrel inserts the butt fusion inslot, and relative drum high-speed rotary motion carries out the butt fusion action, make the drum block the face with the ring form in the outside formation of the butt fusion junction of barrel, prevent effectively that the sizing material after the butt fusion in-process melts from flowing or throwing away, and make the sizing material along keeping off the even packing of gluey ring at the butt fusion inslot, the butt fusion combination cable dish of butt fusion quality prevents the sediment structure effectively. Specifically, the utility model is provided with an annular glue blocking ring at the fusion joint of the disc surface of the upper and lower wire coils and the cylinder body; an annular welding groove is formed between the ring surface of the glue blocking ring and the welding ring, and the width of the annular groove is slightly larger than that of the cable reel cylinder body; during welding, the cylinder is inserted into the welding groove, and molten glue overflowed due to centrifugal action is blocked in the welding groove by the glue blocking ring, so that on one hand, the welding bonding strength is increased, the fluid plastic material in a molten state can be uniformly distributed along the welding groove in the welding process, the welding connection uniformity is ensured, and on the other hand, surface scars or welding slag are avoided; the utility model discloses can cut down the round at barrel joint end surface, this cut down the face and keep off the space of gluing between the anchor ring face and be used for holding and spill over the melten gel.

Example 2: as shown in fig. 4 to 5, in order to implement embodiment 2 of the present invention, a slag-proof structure for welding a combined cable tray includes a tray 7 and a bobbin 8, the bobbin 8 is a cylindrical structure, the tray 7 includes two trays, the two trays 7 are detachably connected to two ends of the bobbin 8 respectively and are fixed to the end of the bobbin 8 by fusion; the welding device is characterized by further comprising a glue blocking ring 4, a welding ring 5 and a welding groove A, wherein the glue blocking ring 4 and the welding ring 5 are of annular structures, the glue blocking ring 4 and the welding ring 5 are arranged at the central position of the side face of the wire coil 7 and are coaxially arranged with the wire coil 7, the inner diameter of the glue blocking ring 4 is larger than the outer diameter of the barrel body 2, and the outer diameter of the welding ring 5 is not larger than the inner diameter of the barrel body; a welding groove A is formed between the glue blocking ring 4 and the welding ring 5 so that the cylinder body 2 can be inserted for welding; when the two ends of the cylinder 2 made of plastic material are respectively welded in the welding groove A in a high-speed rotating motion relative to the two wire coils 7, the glue blocking ring 4 blocks liquid or semi-liquid fluid formed after the cylinder 2 is melted due to high temperature when the cylinder 2 is welded with the two wire coils 7, the liquid or semi-liquid fluid is prevented from overflowing, and after the temperature is reduced, the molten fluid, the glue blocking ring 4, the welding ring 5, the wire coils 7 and the cylinder 2 are connected and fixed into a whole.

The outer side walls of two ends of the bobbin 8 are provided with melt glue surfaces or annular cut-down surfaces 6, the cut-down surfaces 6 are inwards sunken along the outer wall of the bobbin 8 to form annular sunken step surfaces so as to increase the glue containing volume in the glue blocking ring 4; when the first reel body 1 is welded with the bobbin 8, plastic fluid is filled into a gap between the cut-off surface 6 and the glue blocking ring 4, and the reel 7 is fixedly connected with the bobbin 8 after the fluid is condensed and fixed.

The upper part of the welding ring 5 is also provided with a leading-in inclined ring surface B, and the outer side wall of the inclined ring surface B extends outwards gradually from top to bottom so that the leading bobbin 8 is inserted into the welding groove A during welding.

The inner wall of the bobbin 8 may also or alternatively be provided with a guide inclined ring surface B, the inner side wall of which extends gradually inward from the end portion to the middle portion of the bobbin 8, so as to guide the insertion of the cylinder 2 into the welding groove a during welding.

Further, this embodiment is different from the cable dish structure of embodiment 1, and what the cable dish of embodiment 1 adopted is that barrel and second line disk body integration injection moulding, and the injection moulding alone of first line disk body only needs the other end tip of butt fusion first line disk body and barrel in the butt fusion process, consequently, the fender of embodiment 1 glues the ring and only sets up on the side of first line disk body, keeps off and forms the butt fusion groove between inboard and the butt fusion face of glue ring, and the barrel inserts in the butt fusion groove and accomplishes the butt fusion process with first line disk body relative high-speed rotation. In the embodiment, 2 wire coils with the same structure and 1 cylindrical bobbin structure are adopted, and the two wire coils are respectively required to be welded and connected with two ends of the barrel body.

The embodiments of the present invention are only for describing the specific implementation thereof, and are not limited to the scope of protection thereof. The present invention is not limited to the above embodiments, but can be modified in various ways without departing from the scope of the present invention.

Claims

1. A slag-proof structure of a welded combined cable tray comprises a first cable tray body (1), a barrel body (2) and a second cable tray body (3) which are made of plastic materials, wherein the barrel body (2) is of a cylindrical structure, and the first cable tray body (1) and the second cable tray body (3) are arranged at two ends of the barrel body (2) in parallel at intervals; the method is characterized in that: the welding line tray is characterized by further comprising a glue blocking ring (4), a welding ring (5) and a welding groove (A), wherein the glue blocking ring (4) and the welding ring (5) are of annular structures, the glue blocking ring (4) and the welding ring (5) are arranged at the center of the side face of the first line tray body (1) and are coaxially arranged with the first line tray body (1), the inner diameter of the glue blocking ring (4) is larger than the outer diameter of the drum body (2), and the outer diameter of the welding ring (5) is not larger than the inner diameter of the drum body; a welding groove (A) is formed between the glue blocking ring (4) and the welding ring (5) so that the cylinder body (2) can be inserted for welding; when barrel (2) and the first line of disk body (1) of plastics material carry out the butt fusion with high speed rotary motion relatively in butt fusion groove (A), keep off gluey ring (4) and block liquid or the semi-liquid fluid that forms after barrel (2) and first line of disk body (1) butt fusion because of the high temperature, prevent liquid or semi-liquid fluid excessive, and the temperature decline back, the fluid of melt form with keep off gluey ring (4), welding ring (5), first line of disk body (1) and barrel (2) and be connected and be fixed in an organic whole.

2. The slag prevention structure of a welded composite cable tray according to claim 1, wherein: the second reel body (3) and the barrel body (2) are integrally injection-molded to form an integral structure; the first reel body (1) and the barrel body (2) are connected in a melting mode to form an integral cable reel, when the first reel body (1) and the barrel body (2) rotate relatively at a high speed to perform welding, liquid or semi-liquid fluid formed by heating and melting flows along the annular welding groove (A) and is uniformly filled in the welding groove (A); after the welding is finished, when the temperature is reduced, the plastic fluid is condensed and fixed at the welding joint of the first line disk body (1) and the cylinder body (2) to form an annular uniform connecting part.

3. The slag prevention structure of a welded composite cable tray according to claim 2, wherein: the glue melting surface on the outer side wall of the cylinder body (2) is provided with an annular cut-off surface (6), the cut-off surface (6) is inwards sunken along the outer wall of the cylinder body (2) to form an annular sunken step surface so as to increase the glue containing volume in the glue blocking ring (4); when the first line disk body (1) is welded with the cylinder body (2), plastic fluid is filled into a gap between the cut surface (6) and the glue blocking ring (4), and the first line disk body (1) is connected and fixed with the cylinder body (2) after the fluid is condensed and fixed.

4. The slag prevention structure of a welded composite cable tray according to claim 3, wherein: the upper part of the welding ring (5) is also provided with a leading-in inclined ring surface (B), and the outer side wall of the inclined ring surface (B) gradually extends outwards from top to bottom so as to guide the cylinder body (2) to be inserted into the welding groove (A) during welding.

5. The slag prevention structure of a welded composite cable tray according to claim 3, wherein: the inner wall of the cylinder body (2) is provided with a lead-in inclined ring surface (B), and the inner side wall of the inclined ring surface (B) gradually extends outwards from bottom to top so as to lead the cylinder body (2) to be inserted into the welding groove (A) during welding.

6. The slag-proof structure of the welded combined cable reel comprises two wire reels (7) and two bobbins (8), wherein the bobbins (8) are of cylindrical structures, and the two wire reels (7) are respectively detachably connected to two ends of each bobbin (8) and are fixedly connected with the end parts of the bobbins (8) through melting; the method is characterized in that: the welding device is characterized by further comprising a glue blocking ring (4), a welding ring (5) and a welding groove (A), wherein the glue blocking ring (4) and the welding ring (5) are of annular structures, the glue blocking ring (4) and the welding ring (5) are arranged at the center of the side face of the wire coil (7) and are coaxially arranged with the wire coil (7), the inner diameter of the glue blocking ring (4) is larger than the outer diameter of the barrel body (2), and the outer diameter of the welding ring (5) is not larger than the inner diameter of the barrel body; a welding groove (A) is formed between the glue blocking ring (4) and the welding ring (5) so that the cylinder body (2) can be inserted for welding; when the two ends of the cylinder (2) made of plastic material are respectively welded in the welding groove (A) in a high-speed rotating motion relative to the two wire coils (7), the glue blocking ring (4) blocks liquid or semi-liquid fluid formed after the cylinder (2) is melted due to high temperature when the cylinder is welded with the two wire coils (7), the liquid or semi-liquid fluid is prevented from overflowing, and after the temperature is reduced, the melted fluid is connected and fixed with the glue blocking ring (4), the welding ring (5), the wire coils (7) and the cylinder (2) into a whole.

7. The slag prevention structure of a welded composite cable tray according to claim 6, wherein: the glue melting surfaces on the outer side walls of the two ends of the bobbin (8) are provided with annular cut-down surfaces (6), the cut-down surfaces (6) are inwards sunken along the outer wall of the bobbin (8) to form annular sunken step surfaces, so that the glue containing volume in the glue blocking ring (4) is increased; when the first reel body (1) is welded with the bobbin (8), plastic fluid is filled into a gap between the cut-off surface (6) and the glue blocking ring (4), and the reel (7) and the bobbin (8) are connected and fixed after the fluid is condensed and fixed.

8. The slag prevention structure of a welded composite cable tray according to claim 7, wherein: the upper part of the welding ring (5) is also provided with a leading-in inclined ring surface (B), and the outer side wall of the inclined ring surface (B) extends outwards gradually from top to bottom so that a guide bobbin (8) is inserted into the welding groove (A) during welding.

9. The slag prevention structure of a welded composite cable tray according to claim 7, wherein: the inner wall of the bobbin (8) is provided with a lead-in inclined ring surface (B), and the inner side wall of the inclined ring surface (B) gradually extends inwards from the end part of the bobbin (8) to the middle part so as to guide the barrel body (2) to be inserted into the welding groove (A) during welding.